Every hour after you wake up is like having a drink of alcohol.
At the beginning, you’re totally sober. Your thought process is clear.
After a drink, you feel fine. It’s 10am, work is still going smoothly. Two drinks = 11am, you’re still good. Focus is pretty good and you’re getting work done. Your third drink brings your to 12pm, but luckily it’s time for lunch!
You get to eat some food, which cuts the buzz a bit. After lunch you’re feeling a little better, but still kind of drowsy.
The afternoon just keeps going downhill. More hours means more metaphorical drinks and by 4:00 you’re barely able to get anything done. By the end you’re either wild and up for any kind of social activity, or totally exhausted and ready for bed.
What does this all mean?
Certain hours are better for getting certain work done. The beginning of the day is good for highly focused work, while the end of the day might be better for socializing with friends.
Maybe it’s a stretch, but the more I think about it, the more it seems to ring true. See how your day matches up.